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johdex

Sounds in a racing sim

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Hi all, I am working on a racing simulation, and I was wondering how to make realistic sounds, based on the output of the physics engine. Right now, I have two samples, one for the engine, one for skidding. I adjust the frequency of the engine sample according to rpm. I have tried different combinations of affecting the volume and frequency of skidding sounds depending on the "friction speed", "friction ratio", load on the wheels, with little convincing results so far. Any good recipes, anyone?

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according to rpm..."friction speed", "friction ratio", load on the wheels


Since you're dealing with fast enough speeds, you should include the doppler effect(the frequency change when an object is moving towards or away from the listener).

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Original post by josh_w314
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according to rpm..."friction speed", "friction ratio", load on the wheels


Since you're dealing with fast enough speeds, you should include the doppler effect(the frequency change when an object is moving towards or away from the listener).


Yes, that is planned, but first I would like to get the sounds from the vehicle as heard by the driver inside the vehicle. My current implementation is far from satisfactory.

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Sample the engine at fixed points: idle, low RPM, medium RPM and high RPM while on throttle. Sample again while off throttle (lifting). Repeat outside the car (can also just sample outside the car and low-pass filter for inside sound, though the sound is quite different in reality). The samples then need to be pitch corrected and looped (using SoundForge, Audition, etc.). At runtime, the samples are cross-faded based on engine RPM and throttle position. See the FMOD Designer for example sounds and a means to experiment.

See also:

http://members.optusnet.com.au/soundconcepts/index
http://www.gamedev.net/reference/articles/article2317.asp

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Sample the engine at fixed points: idle, low RPM, medium RPM and high RPM while on throttle.


I'm sure this is what you meant, but I'd like to clarify -- for on-throttle samples, you need load to work the engine against. Revving the engine in neutral will yield a completely different sound compared to flooring it [while driving] on the road.

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Original post by ruistola
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Sample the engine at fixed points: idle, low RPM, medium RPM and high RPM while on throttle.


I'm sure this is what you meant, but I'd like to clarify -- for on-throttle samples, you need load to work the engine against. Revving the engine in neutral will yield a completely different sound compared to flooring it [while driving] on the road.


Correct. Additionally, you only need two idle samples: one inside the car (stereo) and one outside the car (mono). Ideally, all the inside car samples are recorded and played back in stereo, while the outside sounds are mono and spatialized to 3D during playback. However, FMODEx, for example, can play back stereo samples in 3D, so placing two mics above the exhaust on both sides of the rear of the car (V6-V12) would allow a more realistic 3D playback.

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Thanks for the tips. I'm not working on a commercial game, so fancy recordings are probably not accessible to me. But at least I know what to look for now.

What about skidding sounds? Are they based on the same principle?

[Edited by - johdex on June 10, 2006 1:17:46 AM]

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